Let’s see how to resize an OpenStack instance. At Bobcares, with our Server Management Services, we can handle your server-related issues.

How to resize an OpenStack instance?

We can increase or decrease the memory or CPU count of the instance by resizing an instance. We can resize the instance that has the necessary capacity by choosing a new flavor for it. After resizing, the instance will rebuild. This will also result in the restarting of the instance.

The openstack server resize command scales a server to a new flavor by creating a new server and copying the contents of the original disk into a new one. The steps to resize an OpenStack instance are as follows:

• Firstly, retrieve the name or ID of the instance that we want to resize. We can use the below command:

  $ openstack server list

   
• Identify the flavor we want to use to resize the instance by retrieving its name or ID using the code:

  $ openstack flavor list

   
• Now we have to do the OpenStack instance resizing:

  $ openstack server resize --flavor <flavor> \
    --wait <instance>

   

  Change flavor with the name or ID of the flavor and instance with the name or ID of the instance that we are resizing. Instance resizing can take a while.
• After the instance resizing, the instance status will change from RESIZE to VERIFY_RESIZE. We should confirm or revert it.

  To confirm it, use the below code:

  $ openstack server resize confirm <instance>

   

  To revert it, use the below code:

  $ openstack server resize revert <instance>

   

We can use the revert option if the resize does not work as expected. This will revert the instance to the old flavor and change the status to ACTIVE.

The openstack server resize command normally gives the operating system the opportunity to conduct a controlled shutdown before the instance is powered off and resized.

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Conclusion

The article explains the steps from our Tech team to resize an OpenStack instance, along with the code to carry out each step.